Cupola

ABSTRACT

A cupola for melting pig iron or steel scrap. The cupola has a belly having a tapping hole at the lower portion thereof, a plurality of more than two spiral combustion chambers provided outside of belly burners. The burners use creosote oil as fuel and direct flame into these combustion chambers. The combustion chambers are provided with tuyeres for blowing flame from the burners into the belly, and the space under the belly is filled with a large number of block-shaped elements of refractory material having a high degree of refractoriness.

United States Patent 151 3,695,601 Okuda et al. 1 51 Oct. 3, 1972 1541CUPOLA 2,161,180 6/1939 Marx ..266/25 [72] Inventors: Kazuo Okuda, No.249, Aza

Kamitahara, Shijonawate; SyoIo Kagimoto, No. 286-13, v Nishiboshima,Minoo, both of Japan 22 Filed: June 2, 1971 [21] Appl. No.: 149,170

[52] US. Cl ..266/25, 266/30 [51] Int. Cl. ..C2lb ll/02 [58] Field ofSearch ..266/25, 29, 30

[56] References Cited UNITED STATES PATENTS 975,826 11/1910 Brown..266/29 1,507,397 9/1924 Moldenke ..266/29 Primary Examiner-Gerald DostAttorney-Wenderoth, Llnd & Ponack [57] ABSTRACT A cupola for melting pigiron or steel scrap. The cupola has a belly having a tapping hole at thelower portion thereof, a plurality of more than two spiral combustionchambers provided outside of belly burners. The burners use creosote oilas fuel and direct flame into these combustion chambers. The combustionchambers are provided with tuyeres for blowing flame from the burnersinto the belly, and the space under the belly is filled with a largenumber of block-shaped elements of refractory material having a highdegree of refractoriness.

2 Claims, 3 Drawing Figures PATE'NTIEBmns m2 SHEET 1 (IF 2 KAZUO OKUDAand SYOZO KAGIMOTO,

I NVENTOR. s

Hula 1M v A'r'roamays mmrcnms 1m sum 2 m 2 KAZUO OKUDA and SYOZOKAGIMOTO,

INVENTOR. S

MM.WL

ATTORNEYS CUPOLA The present invention relates to a cupola for meltingpig iron or steel scrap, particularly to a cupola using heavy oil.

A conventional cupola burns cokes to melt pig iron or steel scrap. Withsuch a method, as the hearth is filled with bed cokes thereon and hotair is blown in from the tuyere to burn cokes to melt pig iron, thequantity of the cokes depends upon the size of the belly and thecharging quantity of pig iron or steel scrap also depends upon thequantity of the cokes, the melting capacity of cupola can not be variedfreely. And after every finish of operation, the hearth is to be opened,and remaining cokes and metal after burning must be taken out, and alsothe operation can not be restarted without repairing and drying thehearth removed therewith, so the efficiency of operation is low.Moreover, as cokes contain much sulphur, exhaust gas contains muchsulphuric dioxide gas and also much soot, there is a defect to expendmuch cost for removing them.

The first object of this invention is to provide a cupola feasible toeliminate such a defect of existing cupola as above described, operablecontinuously and able to reduce melting cost by using heavy oil andblock refractory material.

The second object of this invention is to provide a cupola operableautomatically with usage of heavy oil, particularly creosote oil.

The third object of this invention is to provide a cupola creatinglittle sulphuric dioxide and soot while producing pig iron of excellentquality by using creosote oil. These and other objects may beaccomplished by improvement, combination and operation of each portionconstructing this invention and embodiment thereof will be clear fromthe accompanying drawing and the detailed explanation described later.And, revision or modification with respect to details of theconstruction is to be included in the claim described later.

FIG. 1 is a front view partially sectioned, showing an embodiment of thecupola according to this invention.

FIG. 2 is a cross section on line 2-2 in FIG. 1.

FIG. 3 is a cross sectional plan on line 3-3 in FIG. 1.

The cupola according to this invention comprises a chimney 13 having abelly 11 and a dust arrester 12. The hearth 14 of the belly l 1 isslightly slant, a plurality of tapping ports 15 are formed below thebelly 11 at the lower portion of the hearth. In front of the tappingports 15 is provided a slag separating trough 16, under the front end ofthis slag separating trough I6 is located the fore hearth 17.

On the periphery of said belly 11 is formed the combustion chamber 18.The plan of this combustion chamber 18 is as shown in FIG. 2, at aportion thereof is disposed tangentially the burner fixture 19, a burner20 for burning the creosote oil heated at 50-80 C. is provided on theburner fixture 19. In FIG. 2, the burner fixture 19 is only one, butanother burner fixture 19 may be added as shown with a dot-and-dash linein FIG. 2, and a burner 20 may be disposed on each burner fixture 19.And also, in the belly 11 within the combustion chamber 18 are provideda plurality of tuyeres.

Above the combustion chamber 18 is provided the upper combustion chamber22 surrounding the periphery of the belly 11. Each of the combustionchambers 22 of spiral is disposed at two places as shown in FIG. 3, andeach combustion chamber 22 is provided respectively with the burner 23for burning the creosote oil heated at 50-80 C. similarly with the abovedescription, and in the belly 11 forming the inner side of thecombustion chamber 22 is provided the tuyeres 24 communicating theinterior of the belly 11 and the combustion chamber 22. There areprovided two combustion chambers and two burners respectively in theillustrated embodiment, they may be more than three respectively.

To the upper portion of the belly 11 is connected the heat absorbingtube 25 made with steel plate and the like and the outside thereof isencircled with the air preheating chamber 26. This air preheatingchamber 26 is connected with the blast pipe 28 to the discharge openingof the blower 27 disposed at the side thereof. And, in the intermediateof the blast pipe 28 is provided the damper 29 to regulate the quantityof blast. The lower portion of the preheating chamber 26 and saidcombustion chamber 18,22; are interconnected with plural tertiary airpipes having stop valves 30 in the intermediate thereof respectively,the air from the blower 27 hugs the heat absorbing tube 25 within thepreheating chamber 26 to be heated for making tertiary air of hightemperature, and when required it is to be sent to each combustionchamber 18,22.

Furthermore, to said preheating chamber 26 is also connected thesecondary air pipe 38, and this pipe 38 is connected to the secondaryair port of each burner 20, 23. Namely, each burner 20, 23 spoutsmixture of fuel and air with the primary air of high pressure from thecompressor and blows into the combustion chamber 15 or 22 the mixture onburning it by mixing with the secondary air comprising a large quantityof compressed air of lower pressure from the pipe 38. And, in the outerwall of the combustion chamber 22 is disposed the firing port 39, butthe firing port 39 is closed during burning.

Above said heat absorbing tube 25 is disposed the charging hopper 32. Onthis charging hopper 32 is pro jected the lower opening of the chargingchute 33, on the charging rail 34 arranged between this charging chute33 and the floor is mounted movably up-anddown the charging bucket 36hangable with the hoist 35 located at the upper portion thereof, andwith this bucket 36, pig iron, steel scrap and the like are to becharged into the belly 11.

37 is a plurality of refractory materials of block shape filled from thehearth 14 within the belly up to the middle portion of the uppercombustion chamber 22. These refractory materials are blocks made withsilicon carbide or primary burned carbon having refractoriness of highdegree.

Pig iron, steel scrap, limestone and other desired elements of a properrate are charged on said refractory materials 37 with said bucket 36,and when the blower 27 is started while opening the damper 29 properlyand each burner 20, 23 is started to burn, the flame created by eachburner 20, 23 is flown into the belly 11 from each tuyere 21, 24 whilewhirling within each combustion chamber 18,22, is risen whilered-heating the refractory materials, heats the pig iron and steel scrapon the refractory materials, is further risen through the heat absorbingtube 25 and then is exhausted from the chimney 13. And, the air of hightemperature from the preheating chamber 26 is sent to each burner 20, 23through the secondary air pipe 38 and helps the burner 20, 23 burn, butwhen the quantity of oil spouted from the burners 20, 23 is increasedand the quantity of air is short with respect to fuel, the valve 30 isto be opened to send a large quantity of tertiary air of hightemperature from each tertiary air pipe 31 into each com bustion chamber18, 22 to assist burning. Namely, when the quantity of steel scrap andpig iron to be melted is small, the valve 30 is closed and the cupola isoperated on stopping supply of tertiary air, and when the quantity ofsteel scrap and pig iron is large, then the valve 30 is opened and alarge mass of fuel is to be burned. The point wherein the quantity to bemelted is changeable freely is also a feature of this invention.

The pig iron and steel scrap on the refractory materials 37 is melted bythe operation above mentioned, stored on the hearth 14 through the spacebetween the refractory materials 37, enters the separating trough 16from the tapping port and then is poured into the fore hearth 7 afterseparation of floating slag.

NUMERAL VALUE OF THE EMBODIMENT l. blower (turbo blower) static windpressure 700 mm driving motor 7 k HP blast volume 25 mlmin. No.ofrevolution 3,600 R.P.M. diameter of blast pipe 50 mm 4;

2. charging machine (buckebtype automatic charging device) with 1 HPhoist motor charging rate 50 kg/ a time conveyed to the bucket withmagnetic crane.

(with stop valve) 4. fuel (creosote oil No. l No.4)

calorie No.1, No.2 11,000 12,000 calories No.3, No.4 9,500 10,000calories water below 0.2%

sulphur specific gravity below 0.2% 1.071

Said creosote oil is supplied to the burner after heating up to 50 C.with a heat exchanger using water heated up to C. with an electricheater of l Kw/h.

5. Air compressor for supplying primary air for spouting fuel to theburner.

driving motor 15 HP spouting quantity 2,280 l/min. Capacity of main tank0.28 m pressure 6 Kg/cm 8.5

Kg/cm working pressure in tank 5 Kg/cm burner for drying the fore hearthl proportion of material Charging quantity per a time (for example) FC20 22 1n the case above mentioned, the molten metal is at l,500 C. andhas excellent fluidity, carbonization and decarbonization may beregulated freely.

And also, molten metal tapping quantity is 1,160 Kg/h., as in the caseof conventional diameter of 400 mm (the diameter of the tuyere offurnace), the molten metal tapping quantity is 500 Kg/h, it is clearthat the cupola according to this invention has a capacity larger thantwo times.

We claim:

1. A cupola comprising a belly having tapping hole at the lower portionthereof, plural spiral combustion chambers provided outside of the bellyburners more than two using creosote oil as their fuel for spoutingflame into these combustion chambers, and the combustion chambers areprovided with tuyeres for blowing flame from the burners into the belly,and under the belly are filled with a large number of refractorymaterials of block-shape having refractoriness of high degree.

2. A cupola as claimed in claim 1 wherein a preheating chamber isprovided at the upper belly, which preheats the air supplied from ablast member, and this preheating chamber and each combustion chamberare interconnected with secondary air pipe.

1. A cupola comprising a belly having tapping hole at the lower portionthereof, plural spiral combustion chambers provided outside of the bellyburners more than two using creosote oil as their fuel for spoutingflame into these combustion chambers, and the combustion chambers areprovided with tuyeres for blowing flame from the burners into the belly,and under the belly are filled with a large number of refractorymaterials of block-shape having refractoriness of high degree.
 2. Acupola as claimed in claim 1 wherein a preheating chamber is provided atthe upper belly, which preheats the air supplied from a blast member,and this preheating chamber and each combustion chamber areinterconnected with secondary air pipe.